audio_AlsaAPI.drop is failing on elm, kevin, cave, asuka, banon, snappy, and squawks.

Here's the test error.
TestError: ALSA API failed to drop playback and reset hw_ptron device hw:0,2


This is the error log of elm 10050.0.0.
https://pantheon.corp.google.com/storage/browser/chromeos-autotest-results/150396778-chromeos-test/chromeos2-row7-rack8-host19/debug/

10/20 13:22:04.716 DEBUG|             utils:0280| [stdout] time: 995.945069843 state: 3, avail frames: 12608, hw_level: 52928
10/20 13:22:04.717 DEBUG|             utils:0280| [stdout] Avail frames after drop, prepare, start: 65780
10/20 13:22:04.717 DEBUG|             utils:0280| [stdout] Expected avail frames after drop, prepare, start is 0 - 65586




The test failed in alsa_api_test.c. Jimmy and Chinyue. Any idea?

if (frames < 0 || frames > buffer_frames + fuzz) {
    fprintf(stderr, "Avail frames after drop, prepare, start is %d\n",
            (int)frames);
    exit(1);
}
https://chromium.googlesource.com/chromiumos/platform/audiotest/+/master/src/alsa_api_test.c#403